<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script type="text/javascript">


        var fun =  function (a,b){
            alert("有参函数被调用a=" + a + "b=" + b);
        }

        //重载方法试试看，会【直接覆盖上一次的方法】
        var fun  = function (){
            alert("无参函数方法被调用");
        }


        fun(100,500);
    </script>
</head>
<body>

</body>
</html>